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Researching walking and foot problems

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Matt Smith:

Welcome to the La Trobe University Podcast with myself, Matt Smith. And sitting across from me today is Associate Professor Hylton Menz, director of the Musculoskeletal Research Centre at La Trobe University. Thank you for joining me, Hylton.

Hylton Menz:

My pleasure, Matt.

Matt Smith:

I was hoping you'd, as a bit of a starter, tell me a bit about the research centre. What is its purpose and why was it set up.

Hylton Menz:

The goal of the Musculoskeletal Research Centre is to conduct research into the prevalence, causes and impact of different musculoskeletal conditions and also, to investigate different treatments for these conditions. So, the sort of things that we look into are foot and ankle problems, knee replacement surgery, balance and falls issues in older people and also lower back pain.

Matt Smith:

You said that one of the focuses is on older people but you seem to be approaching foot problems and walking patterns for everyone and you get a lot of sports people going through there, as well, with your research, don't you?

Hylton Menz:

Yeah, we do. One of the good things about the centre is that we conduct research across the full life span, really. So, we do studies into sports medicine. So, we get a lot of football players in to the Gait laboratory. But also, it continues through to older people with osteoarthritis; looking at the effectiveness of different knee replacement surgery techniques. So, it really does encompass the full spectrum.

Matt Smith:

Now, you just mentioned the gait laboratory. What's that?

Hylton Menz:

The gait laboratory is a fantastic facility we got here at La Trobe. It goes over two storeys. It's a very, very large facility. What it includes is a thing called a Vicon motion analysis system. And what that is, it's a reflective marker-based system.

So, you get people walking in the laboratory with markers put on different landmarks of their body. And then, using a range of cameras, you can then configure a three-dimensional picture of how the person's walking and extract all sorts of very useful information about how different joints move, the speed at which the body moves. And then, because we've got that system there, you can use that to look at the effectiveness of different interventions and also to use it as a predictor.

For example, we've used it recently to see whether we can ascertain, whether a sports person is ready to return to playing sport after an injury using the information obtained from the system.

Matt Smith:

In that case, I suppose, it's almost like a test, an evaluator.

Hylton Menz:

Yeah, that's right. I mean, in addition to the motion analysis component of it, we also have equipment down there to assess balance. So, we can look at whether an older person's balance, for example, is impaired and to see whether they may be more likely to experience a fall. And then, we've also got some instrumentation, down there, to look at pressures underneath your foot when you're walking. So, we can see whether there are areas of the foot that are over loaded that we might need to address with different footwear or orthodic modifications.

Matt Smith:

Now, these are sort of things you could tell through over ways. I've seen, if you look at somebody's foot, you with enough experience will be able to see that sort of thing; where problems are, where there needs to be more support.

Hylton Menz:

To some extent, that's true; in that, clinical observations are quite useful for a lot of these investigations. But there are, definitely, areas where you couldn't really pick that up with the naked eye, particularly, with the three-dimensional motion analysis. You can get reasonable information from people walking on a treadmill or walking in a clinic but to really drill down and have a look at that information in detail, you need a motion-analysis system.

Matt Smith:

What is it that got you into this sort of research?

Hylton Menz:

Well, my background is Clinical Podiatry. So, my first degree was at La Trobe, Bachelor of Podiatry. I then, did some lecturing in Podiatry and then decided that I wanted to do a higher degree. I enrolled in a Ph,D., which was actually in Physiology, at the time. So, what I was looking at is balance and fall issues in older people. And then when I did my Post-Doc, I decided to, sort of, fuse those two interests and look at the role of foot problems in older people on mobility and balance.

Matt Smith:

Do you find that there's enough research going on in this area?

Hylton Menz:

There's a lot of falls and balance research going on, I guess, in a generic sense. But there wasn't much going on specific to the foot and ankle. And I guess, that's the original contribution I've been able to make by combining my clinical background with the physiology part of my Ph.D.

So, really it's one of those areas that people had touched on a little bit before but no one had really exploited in detail. So, that's been the really exciting part of the research over the last few years.

Matt Smith:

You've recently done a six-year study into foot problems on older women. Can you tell me a bit about that and why did you approach older women, specifically, as a target in that research?

Hylton Menz:

Yeah, well, that particular project's collaboration with the Australian Longitudinal Study of Women's Health which is conducted through the University of Newcastle and the University of Queensland. Now, this is a big study. It's been going on for several years now.

What they've done, is they've recruited some three different cohorts of women; young, middle-aged and old women. And then, they followed these people up every three years. So, it's a big postal survey. And one of the things that I was interested in doing with that particular data set was to see what happens overtime. Because even though we had some good information from studies where they just looked at people at one time point; no one had ever looked to see what happens with these people when you follow them up.

So, because this data set was already available; we put in a data request to conduct an analysis, specifically looking at the foot problems in older women. And the reason where interested in looking at older women is that, by far, they have a much higher prevalence of foot problems than men. And so, there's a real need to, sort of, tease out why that might be.

Matt Smith:

That's, actually, kind of surprising. Did you find what the difference was there?

Hylton Menz:

Well, one of the main questions with this particular study was to try and work out, what are the factors that might influence whether older women with foot problems get a resolution of their foot problems overtime or which foot problems will persist.

So, what we did was we divided the group at baseline and follow up into four different categories. I just have to explain those as soon we're at the context.

The first group was people who had no foot problems, either at baseline or six years later. So we just called them as having 'no foot problems'. The second group were those who had no foot problems at baseline but then they did report a foot problem, six years later. So we called those 'new foot problems' or 'incident foot problems'. The third group of people who had a foot problem at baseline and at follow up. So, there were persistent foot problems. And in the fourth group of people who had a foot problem at baseline but then by the time we tested them at six years, they had resolved their foot problem.

So, what we're able to do, looking at those four groups of people, to try and work out what other factors that influenced whether someone's foot problems go away or whether it stays with them six years later.

Matt Smith:

Just as a guess, I'd say the majority of problems don't go away.

Hylton Menz:

That's the interesting part of it. Because there have been, I guess, a general sort of feeling that once you get to that age; if you've got a foot problem, you're pretty much stuck with it. Or if you've got to that age without having foot problems, then you'd be pretty free of foot problems for the rest of the time.

But the surprise of the study showed that it was actually more dynamic than that; in that, if you were an older woman—over the age of 70—who didn't have a good problem at baseline there's about a 50% chance that you would develop a foot problem over that six year period which is quite high.

And then the other interesting factor was for those women who did have a foot problem; about half of those would resolve over a six-year period and half would persist. So, it's certainly a lot more dynamic than we thought.

The information that we obtain from the study is quite useful and will have some implications for future treatment. Because the main factor that seem to be associated with both the onset of new foot problems and also, the persistence of existing foot problems was an increase in body mass index which is a measure of your weight relative to your height.

So, those that put on more weight relative to their height over that six-year period were more likely to develop a new foot problem—if they didn't have one before. And also, if they did have a foot problem they were more likely for that foot problem to persist. So, that does seem to be the strong link between body mass index and foot problems.

Matt Smith:

If you took that correlation on a bit more then you'd assume that since Australia's population seems to be getting heavier as years go on; we're going to see more foot problems in older people.

Hylton Menz:

Yeah, I think, that's definitely the case. Even with younger people; we've done some previous studies associated with the Northwest Satellite health study which included people over a much broader age range. The surprising finding there was, even in fairly young people in their 20s and 30s, being overweight or obese was very strongly associated with foot problems in them, as well.

So, given that we do seem to have these increasing obese epidemic, you could infer that we're going to see more foot problems as a result of that.

Matt Smith:

But what is the defining thing that you're using as a foot problem? What are calling a foot problem?

Hylton Menz:

Yeah, that's a good question. That's actually one of the limitations of the literature in this area. Over the years, people have used different definitions. The definition used in this most recent study of older women was a single question that simply asked, "Do you have problems with one or both of your feet?" And that was categorized as: really, sometimes, most of the time or often. And then you can just create a dichotomous yes / no response from that.

More recently, what we've started to use is a tool called a Manchester Foot Pain and Disability Index. That's a 17-item questionnaire which gives you a lot more detail and you can break it down into components. You can break it down into a foot pain component but also a functional component, as well.

And I think, that's the tool that people should be using from here on in because it does give you a lot more detail as to, precisely, what the foot problem is.

Matt Smith:

If in the survey, you did ask people, "Do you have a foot problem?", they could say 'yes' for everything up to 'I need to cut my toenails' right through to 'I just lost a toe'

Hylton Menz:

Exactly. Yeah, there is a limitation there; in that, what people perceive to be a foot problem various—hugely. And in fact, in older people, one of the issues that might create problems will be something as simple as having difficulty finding comfortable shoes, could be a foot problem; whereas, as you're suggesting, that could extend all the way through to fairly serious complaints.

So, there are always limitation with these postal surveys, it is all driven by participants; as to how they perceive these things. But the benefit of them is that you can do it on very large numbers of people. The alternative approach is to, actually, get people into a clinic and do detailed foot assessments. But that's a lot more expensive; takes a lot more time. But then, the benefit of that approach is that you get a lot more clinical detail.

So, ideally, what you need to do is combine the two ends and sort of finding a middle ground between big samples but also a lot of details in the assessments.

Matt Smith:

You said a bit earlier that one of the problems that could be reported is that they have trouble finding comfortable shoes. And I suppose that this is going to be a problem that becomes more prevalent where young people are getting shoes for more, say, fashion items and not because they're good footwear that give you support. Are humans better off without shoes? Are shoes a good thing or do they cause more problems than they're worth?

Hylton Menz:

There's definitely a need to have some sort of foot covering. Very few of us would be able to get around without any sort of footwear. But it's also true that what's happened over the years is that shoes have been designed really for fashion factors rather than functional factors.

So, particularly in women, there are feature of shoes that might be aesthetically pleasing but do have some impact on foot health. And the obvious ones are heel elevations or high-heels and also the shape of the toe box—the front part of the shoe—which in women's shoes are quite pointed whereas in men's shoes it's a lot broader.

And we have found, certainly, with previous studies shown that there is a strong link between women's footwear and the development of foot problems, particularly in the front part of the foot.

Matt Smith:

So, should they need to take it easy on high-heel shoes?

Hylton Menz:

Yeah, I mean, I think the recommendation we're suggesting now, as Podiatrists, is if you do need to wear high-heels on the odd occasion, that's fine. But wearing an elevated-heel shoe on a regular basis is something that we would, definitely, advise against.

Matt Smith:

Recently, Men's Style Magazine voted you as a man of influence. How does that feel? What does it take from your perspective to become a man of influence?

Hylton Menz:

That was quite a different sort of accolade. I certainly haven't received anything like that before. As a researcher, it's not the sort of thing that you do necessarily seek out. So, it was a bit of a surprise but it was a nice bit of recognition of the work that we're doing.

As being a 'man of influence', I'm not sure how much influence I've had, so far. But certainly, one thing we've managed to do at La Trobe here is that we have really started to get a good group of people together doing foot and ankle research. We'd, probably, do more foot and ankle research at La Trobe than any other centre in Australia, at the moment. So, that's something I'm quite proud of. My net's driven—I work by some very, very talented PhD students. So, if I'd had any influence on them, hopefully, it's been a positive one.

Matt Smith:

And what's the next step for your research?

Hylton Menz:

There are several threads to the research program we've got going at the moment. We have quite a few randomized clinical trials; looking interventions to different foot conditions which, sort of, finishing up this year. So, we have a trial, looking at whether an injection into your big toe joint is effective for arthritis in that joint? And we're just about finishing the results on that one.

We also have a large trial; looking to see whether Podiatry can prevent falls in older people. And again, that one's just finalizing the results now. But in terms of future studies; for me, personally, I'll be looking at continuing on, specifically, looking at foot problems in older people and the why we can sort of design more effective treatments.

And one step, I guess, extending from this current study of older women is to try and tease out exactly what the increase in body mass—how it's driving that relationship with foot problems. And the reason for that is it could be just a simple mechanical factor. The fact that you're heavier, you could be putting more force through your feet; that's what's creating the foot problem.

Or it could be something that actually more metabolic. What I mean by that is that we had some data, recently, to show that fat mass as opposed to skeletal muscle mass is more strongly associated with foot problems. And we know that adipose tissue or fat tissue does produce inflammatory cytokines which have an impact on sensitizing nerve receptors and can, therefore, be associated with pain.

So, it could be a little bit complex than just being heavier and then putting more weight through your feet; it could be a metabolic component, as well. So, I came to look into that and tease out a little bit more detail.

Matt Smith:

That's all the time we've got for the La Trobe University Podcast today. If you'd like to send an email and give feedback or ask questions about this podcast or any other, you can drop us a line at podcast@latrobe.edu.au. Hylton Menz, man of influence, thank you for your time, today.